CVE-2026-73270

httpd mod_auth directory protection bypassed by request path casing on case-insensitive filesystems

Products / packages Erlang OTP

Published 01/09/2026, 14:48:53 UTC

Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 15/11/2026, 03:00:33 UTC

EEF · CVSS:4.0 · 8.2

Assessment vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Severity

high8.2

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Source guidance available

Review the recorded instructions. Guidance may be a workaround rather than a fixed version.

What this means

Erlang/OTP's httpd mod_auth has a vulnerability that allows a remote unauthenticated attacker to read files inside a protected directory by requesting them with different casing on case-insensitive filesystems, affecting OTP versions from 17.0 to 27.3.4.17, 28.5.0.6, and 29.0.6. Whether versions before 17.0 are affected is unknown.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Erlang · EEF

OTP

1 range

EEF version evidence

Package identity

pkg:software-id/erlang.org/otp

Identity supplied by EEF. Version matching requires compatible range evidence.

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

17.0 → before *

otp versions

From 27.3.4.17: unaffected

From 28.5.0.6: unaffected

From 29.0.6: unaffected

Source order retained; this version scheme requires manual review.

Other versions: unknown

Product identifiers (CPE)

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

Erlang · EEF

OTP

1 range

EEF version evidence

Package identity

pkg:otp/inets?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%2Bhttps:%2F%2Fgithub.com%2Ferlang%2Fotp.git

Identity supplied by EEF. Version matching requires compatible range evidence.

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

5.10 → before *

otp versions

From 9.3.2.7: unaffected

From 9.6.2.3: unaffected

From 9.7.2: unaffected

Source order retained; this version scheme requires manual review.

Other versions: unknown

Product identifiers (CPE)

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

Erlang · EEF

OTP

4 ranges

EEF version evidence

Package identity

pkg:github/erlang/otp

Identity supplied by EEF. Version matching requires compatible range evidence.

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

84adefa331c4159d432d22840663c38f155cd4c1 → before *

git versions

From bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6: unaffected

From d8878dec0ececc2eab18e47bb18b472f224ca633: unaffected

From 9641944a2efbf55bea760f8ff7ba777fe3a0961c: unaffected

Source order retained; this version scheme requires manual review.

unaffected

bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6 → before *

git versions

d8878dec0ececc2eab18e47bb18b472f224ca633 → before *

git versions

9641944a2efbf55bea760f8ff7ba777fe3a0961c → before *

git versions

Other versions: unknown

Product identifiers (CPE)

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

Host the document root on a case-sensitive filesystem, where the mismatched casing does not resolve to the protected file.
Place a reverse proxy in front of httpd that performs its own case-insensitive path matching for the protected paths, or that normalises request path casing before forwarding.
Restrict access to the server to trusted clients where the deployment allows it.

EEF guidance ↗

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a mod_auth protected directory by requesting them with different casing, on deployments whose filesystem is case-insensitive.

mod_auth:secret_path/3 decides whether a resolved filesystem path lies inside a protected directory block by running the configured directory path through re:run/3 without the caseless option. A request for /secret/file against a directory configured as /Secret therefore does not match, so the request is treated as unprotected and no authentication challenge is issued, while the filesystem resolves the differently cased path to the same file and mod_get serves it. Deployments on case-sensitive filesystems are unaffected, because there the filesystem itself rejects the mismatched casing.

This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, OTP 28.5.0.6, and OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, 9.6.2.3, and 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

References

7 sources

erlang/otp · security/advisories/GHSA-mh78-93cr-jx8f

Vendor advisoryEEF

erlang/otp · commit bac19eb

PatchEEF

erlang/otp · commit d8878de

PatchEEF

erlang/otp · commit 9641944

PatchEEF

cna.erlef.org/cves/CVE-2026-73270.html

Security advisoryEEF

osv.dev/vulnerability/EEF-CVE-2026-73270

Security advisoryEEF

View 1 more references

www.erlang.org/doc/system/versions.html

Source referenceEEF

Inside the record

Evidence available

Package identity

Version evidence

Remediation guidance

Weakness classification

Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-73270

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-178 ↗

CWE-178 Improper Handling of Case Sensitivity

EEF

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

EEF · platform conditions

All conditions must hold

Any condition may hold

Vulnerable product

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

From (inclusive):

After:

Through (inclusive):

Before: 27.3.4.17

Vulnerable product

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

From (inclusive): 28.0

After:

Through (inclusive):

Before: 28.5.0.6

Vulnerable product

cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

From (inclusive): 29.0

After:

Through (inclusive):

Before: 29.0.6

Applicability preview

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  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "27.3.4.17",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "28.5.0.6",
            "versionStartIncluding": "28.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "29.0.6",
            "versionStartIncluding": "29.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "AND"
  }
]

Contributing organizations · 2

EEF

Assigning organization

2026-11-11

CISA-ADP

Additional data publisher

2026-09-01

Timeline

All times UTC

1 Sept 2026, 14:48
Advisory published
Publication date supplied by the source.
11 Nov 2026, 13:43
Source updated
Latest modification date supplied by the source.
11 Nov 2026, 14:49
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: 0.93% estimated probability in the next 30 days. 2026-11-10 · FIRST EPSS.

CISA-ADP · SSVC

CISA Coordinator · 2026-09-01

Exploitation: none
Automatable: no
Technical Impact: partial

SSVC describes the publisher’s decision context. Your organization’s exposure and priorities may differ.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-73270